Veterinary parasitology, regional studies and reports2023; 39; 100843; doi: 10.1016/j.vprsr.2023.100843

Case report: Halicephalobus gingivalis in a Tennessee pony.

Abstract: A 17-year-old female grade pony presented to University of Tennessee Veterinary Medical Center in May of 2021 for evaluation of multifocal, firm, sessile, circular lesions of various diameters on the ventrum and flank. The lesions had been present for two weeks at presentation. An excisional biopsy found numerous adult and larval rhabditid nematodes most consistent with Halicephalobus gingivalis. PCR targeting a portion of the large ribosomal subunit confirmed this diagnosis. The patient was treated with a high dose course of ivermectin followed by fenbendazole. The patient began showing neurologic signs five months after initial diagnosis. Due to the poor prognosis, euthanasia was elected. PCR of CNS tissues confirmed the presence of H. gingivalis in the brain, and one adult worm and several larvae were found on histologic sections of the cerebellum. H. gingivalis is a rare but lethal disease of horses and people.
Publication Date: 2023-02-13 PubMed ID: 36878634DOI: 10.1016/j.vprsr.2023.100843Google Scholar: Lookup
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Summary

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The research article discusses a case of Halicephalobus gingivalis infection in a 17-year-old female pony in Tennessee, which eventually led to neurological symptoms and euthanasia.

Case Presentation

  • The pony in question was brought to the University of Tennessee Veterinary Medical Center in May 2021. It was presenting with firm, round lesions of varying sizes on its lower body and flank.
  • The lesions had been present for two weeks before the pony was taken to the center.

Diagnosis

  • An excisional biopsy was conducted on the lesions. Upon examination, it was discovered that these lesions contained several adult and larval rhabditid nematodes. The characteristics of these nematodes pointed to Halicephalobus gingivalis.
  • The diagnosis was further confirmed using PCR (Polymerase Chain Reaction), a commonly used molecular biology technique that targets a portion of the large ribosomal subunit.

Treatment and Progress

  • The pony was initially treated with a high dose course of ivermectin, an antiparasitic medication, followed by fenbendazole, another antiparasitic drug.
  • Despite the treatment, the pony began showing neurological symptoms five months after the initial diagnosis. This indicates that the infection had spread to central nervous system.
  • Due to the poor prognosis and worsening condition of the pony, the decision to euthanize it was made.

Post Mortem Examination

  • PCR was conducted on the pony’s brain tissues after euthanization. The results confirmed the presence of H. gingivalis in the brain.
  • Upon examination of histologic sections of the cerebellum, one adult worm and several larvae were found, indicating that the infection had indeed spread to the brain.

Potential Implications of the Case

  • This case emphasizes that H. gingivalis, although a rare infection, is lethal. H. gingivalis can infect both horses and humans.
  • The ability of the nematode to invade and cause neurological problems also reflects its severity and the challenges it poses for treatment.

Cite This Article

APA
Baker E, Geick A, Hines M, Gerhold R, Cordero-Aponte C. (2023). Case report: Halicephalobus gingivalis in a Tennessee pony. Vet Parasitol Reg Stud Reports, 39, 100843. https://doi.org/10.1016/j.vprsr.2023.100843

Publication

ISSN: 2405-9390
NlmUniqueID: 101680410
Country: Netherlands
Language: English
Volume: 39
Pages: 100843
PII: S2405-9390(23)00013-8

Researcher Affiliations

Baker, Eliza
  • Biomedical and Diagnostic Sciences, University of Tennessee, 2407 River Drive, Room A233, Knoxville, TN 37996, USA. Electronic address: eburbank@vols.utk.edu.
Geick, Abby
  • Large Animal Clinical Sciences, University of Tennessee 2407 River Drive, Knoxville, TN 37996, USA.
Hines, Melissa
  • Large Animal Clinical Sciences, University of Tennessee 2407 River Drive, Knoxville, TN 37996, USA.
Gerhold, Richard
  • Biomedical and Diagnostic Sciences, University of Tennessee, 2407 River Drive, Room A233, Knoxville, TN 37996, USA.
Cordero-Aponte, Camille
  • Biomedical and Diagnostic Sciences, University of Tennessee, 2407 River Drive, Room A233, Knoxville, TN 37996, USA.

MeSH Terms

  • Female
  • Animals
  • Horses
  • Tennessee
  • Rhabditida
  • Biopsy / veterinary
  • Brain
  • Fenbendazole
  • Larva

Conflict of Interest Statement

Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Citations

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